Gemini Observatory Press Releases

Brown Dwarf Found Around Nearby, Sun-Like Star

Media Image Resources

For more information, please see the press release.
Illustration of 15 Sge

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15 Sge is a star very much like our sun that is located 57.7 light years away. The star is much larger than the object orbiting it, but looks small in this view because it is farther away.

Orbiting far from the star is a companion about 65 times the mass of Jupiter. It is a brown dwarf, more massive than a planet, but too small to produce energy by nuclear fusion as a star does. It is glowing with its own heat.

This image must be credited to "Gemini Observatory".


AO image of 15 Sge

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The Gemini North Telescope using the University of Hawaii's Hokupa'a adaptive optics system found a very faint companion orbiting around 15 Sge (left). The same Gemini data have been processed to show the brown dwarf companion more clearly (right). The brown dwarf lies only 0.8 arc seconds from the primary. (The fainter ripples are artifacts of the image processing.) The brown dwarf is located at about the 7:00 position on these images.

Gemini-North adaptive optics image of 15 Sge and its newly found companion (15 Sge B). The data was obtained in the near-infrared, at a wavelength of 2.2 microns. The image has been computer processed to subtract the light from the much brighter primary star in the vicinity of the companion.

This image must be credited to "Gemini Observatory/University of Hawaii Institute for Astronomy/Michael Liu/NSF".


Merged AO image of 15 Sge

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This image is a merger of the two images above that highlights the brown dwarf image around Sge 15 that was revealed for the first time by Gemini.

This image must be credited to "Gemini Observatory/University of Hawaii Institute for Astronomy/Michael Liu/NSF".


K-band image of HR7672B

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Keck adaptive optics image of 15 Sge and its companion, also obtained in the near-infrared. The arrow points to the companion, seen as a close point source. (The streaks of light around the primary star are image artifacts produced by the telescope.) Orientation and size are the same as the above Gemini image.

This image must be credited to "W. M. Keck Observatory/University of Hawaii Institute for Astronomy/Michael Liu".


Starmap of location of 15 Sge

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15 Sge is a star located in Sagitta ("The Arrow"), a small constellation in the Summer Triangle. 15 Sge is barely visible to the naked eye on a clear night far from city lights.

This image must be credited to "Gemini Observatory".


Illustration of solar system

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The brown dwarf, which astronomers named 15 Sge B, orbits its star at a distance of 14 A.U., or about 1.5 times Saturn's distance from the Sun.

This image must be credited to "Gemini Observatory".

Artwork by Jon Lomberg. Photo Credit: "Gemini Observatory".


Ruth A. Kneale / web@gemini.edu / January 7, 2002